Sentry / Slack integration issue with popup on resolve/archive buttons

### Self-Hosted Version

25.7.0

### CPU Architecture

x86_64

### Docker Version

28.3.0

### Docker Compose Version

2.37.3

### Machine Specification

- [x] My system meets the minimum system requirements of Sentry

### Steps to Reproduce

when allert appears in slack and trying to push resolve pop-up menu doesn't appear

### Expected Result

when pushing on alert resolve pop-up, it doesn't appear. for few peaoples OK but for doesn't work for most...

### Actual Result

nginx logs shows
+0000] "POST /extensions/slack/action/ HTTP/2.0" 200 0 "-" "Slackbot 1.0 (+https://api.slack.com/robots)" "0.205" ratio="-" body="-" Host="sentry.somehost.com" X-Host="-" X-Nord-Host-Orig="-" debug="-" cache="-" country="IT"

### Event ID

_No response_

The payload names no source file or test. Start by reproducing the Slack resolve/archive action on self-hosted Sentry 25.7.0, then inspect the POST /extensions/slack/action/ request, response, and nginx logs. Done means the popup appears and the action works consistently for affected users.

Written by the indexing model from the issue text.